A145928 - OEIS

A145928

Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.

1, 1, 1, 3, 10, 33, 134, 947, 8780, 97821, 1375312, 27712816, 754977953, 26645291289, 1208294585650, 74271003442168, 6124346294290730, 668846422203976047, 95426817845827533968, 18141398847837127162392

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OFFSET

1,4

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

Maximal 8 X 8 example

.0.0.0.1.0.0.0.1

.0.0.1.1.0.0.1.1

.0.1.0.1.0.0.0.1

.1.1.1.0.1.1.1.0

.0.0.0.1.0.1.0.1

.0.0.0.1.1.0.1.1

.0.1.0.1.0.1.0.1

.1.1.1.0.1.1.1.0

CROSSREFS

Sequence in context: A024426 A326558 A149031 * A006535 A041633 A308499

Adjacent sequences: A145925 A145926 A145927 * A145929 A145930 A145931

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 25 2008

STATUS

approved